Re: [tip:core/signals] signals/sigaltstack: Prepare to add new SS_xxx flags
From: Andy Lutomirski
Date: Tue May 03 2016 - 12:45:06 EST
On Tue, May 3, 2016 at 9:13 AM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
> On Tue, May 3, 2016 at 12:50 AM, tip-bot for Stas Sergeev
> <tipbot@xxxxxxxxx> wrote:
>> Commit-ID: 407bc16ad1769f5cb8ad9555611cb198187ef4cd
>> Gitweb: http://git.kernel.org/tip/407bc16ad1769f5cb8ad9555611cb198187ef4cd
>> Author: Stas Sergeev <stsp@xxxxxxx>
>> AuthorDate: Thu, 14 Apr 2016 23:20:03 +0300
>> Committer: Ingo Molnar <mingo@xxxxxxxxxx>
>> CommitDate: Tue, 3 May 2016 08:37:59 +0200
>> signals/sigaltstack: Prepare to add new SS_xxx flags
>> This patch adds SS_FLAG_BITS - the mask that splits sigaltstack
>> mode values and bit-flags. Since there is no bit-flags yet, the
>> mask is defined to 0. The flags are added by subsequent patches.
>> With every new flag, the mask should have the appropriate bit cleared.
>> This makes sure if some flag is tried on a kernel that doesn't
>> support it, the -EINVAL error will be returned, because such a
>> flag will be treated as an invalid mode rather than the bit-flag.
>> That way the existence of the particular features can be probed
>> at run-time.
>> This change was suggested by Andy Lutomirski:
Correction: does not LGTM. In a sensible design, sigaltstack would
report flags back to the caller. I will send a fix.